Mechanistic insights into the role of branched polyethylenimine in breaking Asphaltene-Stabilized Oil-in-Water emulsions: Temperature effects
Bibliographic record
Abstract
• Branched PEI effectively demulsifies asphaltenes-stabilized O/W emulsions. • PEI disrupts asphaltene films, reducing steric and EDL repulsions among droplets. • Cationic PEI bridges asphaltene films, promoting droplet coalescence. • Elevated temperatures weaken asphaltene films, aiding PEI in film disruption. • Elevated temperatures enhance demulsification and droplet coalescence by PEI. The stabilization of oil-in-water (O/W) emulsions by natural emulsifiers like asphaltenes poses significant economic and environmental challenges in oil production. Elevated temperatures in actual production strongly influence the demulsification processes. In this study, the performance of branched polyethylenimine (PEI), a reverse emulsion breaker (REB), in demulsifying asphaltenes-stabilized O/W emulsion was evaluated across different temperatures using bottle tests and detailed phase characterizations. Using techniques including dynamic interfacial tension (DIFT) measurements, atomic force microscopy (AFM) imaging, contact angle measurements, coalescence time measurements, and surface force measurements, the demulsification mechanisms of this PEI-type REB and the effect of temperature were comprehensively explored. The results indicate that PEI-type REB neutralizes the surface charges of oil droplets, induces reconfiguration and reorientation of asphaltenes, and disrupts the rigid interfacial films, reducing steric hindrance and electrical double layer (EDL) repulsion among oil droplets. Moreover, cationic REB molecules can bridge the negatively charged asphaltene films surrounding oil droplets. The combined effects of weakened interfacial films, reduced repulsions among oil droplets, and REB bridging promote droplet coalescence, thereby improving demulsification. While increasing temperature slightly reduces REB adsorption at the interfaces, it enhances demulsification by weakening the asphaltene films, lowering droplet surface charges, and reinforcing the bridging effect of REB molecules, collectively promoting droplet coalescence. This study offers critical insights into the interfacial interactions between asphaltenes and REB at different temperatures, advancing the understanding of O/W emulsion demulsification mechanisms and guiding the development of effective REBs for enhanced oil–water separation, particularly under high-temperature conditions in the petroleum industry.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".